Grafted polyolefin compositions, including polypropylene homopolymers and copolymers grafted with glycidyl acrylate and glycidyl methacrylate, are previously known in various applications, but such compositions have not been obtained by melt processing of the polyolefin composition.
SE 393,385 teaches the production of modified (grafted) polyolefins in a particulate form, having improved adhesion properties, especially an improved adhesion to materials having polar groups such as glass. A particulate .alpha.-olefin polymer having 2 to 10 carbon atoms is mixed with an organic peroxide as a radical-generating compound and a polymerizable compound selected from the group of glycidyl acrylate and glycidyl methacrylate, and the mixture is reacted in an inert atmosphere at a temperature below the tackyfying temperature of the polymer, to obtain directly from the reaction a modified (grafted) particulate polyolefin. Thus, no melting of the polymer is effected. The reaction is carried out in a reaction zone of the fluidized bed type or in a heated jacketed vessel provided with mixing means.
DE 2,440,668 teaches a filled polyolefin composition produced from a mixture of a molten polyolefin, an organic peroxide, a polar vinyl monomer and a porous filler, preferably a wood flour, the latter being preferably used in an amount of 20% to 60% by weight of the polyolefin. The polyolefin has an isotactic index of at least 80% and is preferably an isotactic polypropylene. The polypropylene can be mixed with up to 15% by weight of another .alpha.-olefin. Mentioned among preferred vinyl monomers is i.a. glycidyl methacrylate, which has a good affinity for wood flour. The powdery mixture is processed in a kneader extruder (LD=22) at 150.degree.-185.degree.-180.degree. C. (feeding zone--metering zone--die) and is then granulated. The process is aiming at obtaining a filled PP composition that can be processed by injection moulding or extrusion to give articles having good mechanical properties.
EP 0274744 teaches modified, elastomeric ethylenepropylene copolymers (EPDM) for addition to common thermoplastic resins, such as polycarbonates, polyesters, polyphenyene ethers, polyimides, polyamides, etc., to achieve improved impact resistance, especially in the knitlines of articles manufactured by injection moulding. The compositions are obtained by a graft polymerization reaction, wherein the EPM or EPDM composition is grafted in an extruder with an unsaturated hydrocarbon compound having an epoxy functionality, in the presence of a peroxide catalyst. The preferred unsaturated hydrocarbon compounds having an epoxy functionality, are glycidyl compounds, particularly glycidyl methacrylate. During the production of the EPM or EPDM composition, a mixture of the unsaturated hydrocarbon compound having epoxy functionality, and the peroxide catalyst, is added in the extruder at a position shortly downstream of the hopper. It is essential that the EPM/EPDM composition should have a degree of cross-linking corresponding to a gel content of at least 5%. When the modified polymer composition is dispersed as discrete particles in thermoplastic compositions, the impact resistance of such compositions is improved.